27-10-2012, 12:53 PM
Exactly, Lawrence - which is what my earlier thread detailed.
Joe: that valve you've shown isn't an EBC33: it looks very much like a 6K8G. The EBC33 looks like an EF39, complete with metallising screening. Incidentally, if any of those EF39 valves have lost their outer metallic coating, they will give trouble. That outer coating is joined to pin 1: use an Ohmmeter to check for continuity, even if all the metallising is intact. Any deficiencies in that metallising screening will certainly produce an unstable amplifier if it is in an I.F. or R.F. amp. stage: and in the PCR there are three such stages.
Al.
Joe: that valve you've shown isn't an EBC33: it looks very much like a 6K8G. The EBC33 looks like an EF39, complete with metallising screening. Incidentally, if any of those EF39 valves have lost their outer metallic coating, they will give trouble. That outer coating is joined to pin 1: use an Ohmmeter to check for continuity, even if all the metallising is intact. Any deficiencies in that metallising screening will certainly produce an unstable amplifier if it is in an I.F. or R.F. amp. stage: and in the PCR there are three such stages.
Al.
